Three dimensional objects manufacturing processes involve deposition of a curable material layer in an imagewise manner and curing or hardening of the deposited segments of the layer. The layers are deposited (added) on top of each other and hence the process is called an additive manufacturing process by means of which a computer generated 3D model is converted into a physical object. The process involves generation of a plurality of material layers laid down or deposited on top (or bottom) of each of the preceding layer until the amount of accumulated layers results in a desired three dimensional physical object.
The material from which the layers of the three-dimensional physical object are generated could come in liquid, paste, powder, gel and other form. Conversion of such materials into a solid form is typically performed by suitable actinic radiation or heat. Different manufacturing techniques such as inkjet printing, laser sintering, material extrusion and others are used for manufacture of 3D objects.
Manufacturing of 3D objects spans over a large range of applications. This includes prototype manufacture, small runs of different products manufacture, decorations, sculptures, architectural models and other physical objects.
One of the common sources of curing radiation are Ultraviolet (UV) light sources. The time required to build a three-dimensional object depends on various parameters such as for example, curing time of the material using UV radiation, the speed of adding solid or liquid material to the layer which depends on the material itself, layer thickness, the intensity of the curing agent and the desired resolution of the three-dimensional object details and others.
Material extrusion supports manufacture of 3D objects and the curing of the extruded material could be performed in local or regional curing mode. However, since the extrusion nozzle is relatively close to the material deposited on the topmost layer of the model being deposited, curing radiation, such as UV radiation, aimed at curing the extruded layer reaches the nozzle as well, curing any material residues adhered to the external surface of the nozzle and/or inside the nozzle opening forming cured residues that may compromise the accuracy of the printing process by bringing about dislocation or deviation of the deposited material or full or partial blocking of the nozzle opening, which may bring about deposition of less material than required or gaps in material deposition.
Protecting the nozzle from curing UV radiation may prevent accumulation of cured residues around or inside the nozzle opening and allow smooth and accurate printing.